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I overfilled my bike with oil about a month ago and it's developed a noticeable leak. As of yesterday, my bike would leave a tiny puddle of dirty oil wherever I parked it. Also, while riding, if I got on the gas any harder than a blip here or there, drops of oil would be flung from the engine onto my legs. It was especially bad today, I rode home going, "ooh, oww, ahhh, dang!" for about 10 minutes as super hot oil continuously hit my shins. I assumed it was the base gasket because that's where so much oil seemed to be coming from, but after reading on here a bit, it seems that it's probably the cam chain tensioner gasket.

I decided to replace the cam chain tensioner gasket today. First, it was a real pain in the rear getting that dang thing out of there without removing the header pipe. I didn't want to remove the header pipe because I was just sure I'd mess up those gaskets too in the process, so I did the whole thing with the header in place. At one point it seemed like I had three hands! I didn't have the gasket on hand, but I did have cork/rubber gasket material. I made a new gasket out of that, and it seems okay so far, but that's not what I'm worried about. I'll order a proper gasket soon.

I set the engine to top dead center, assuming that since all the valves would be closed, I didn't have anything to worry about. But, I don't know what stroke the engine was on when I set it to TDC and removed/replaced the cam chain tensioner. On the ride home I was getting backfire all the time, rather than just on deceleration, and the engine kept cutting out on me when I'd let it idle in between stops. My question is, is the timing messed up? Did I remove the cam chain tensioner on the wrong stroke? How can I check these things, and what should I do if I've messed things up?

how much oil is in your airbox ???

Perfect timing for this post (no pun intended)
I suppose the real question to ask is the top dead center that you use to adjust valves the same top dead center you use to adjust/farkle with the timing chain tensioner?

If so.. then the TDC you use is the one that as you keep turning past the TDC mark, the valves don't move.

Somebody please confirm or reject

None, it all seems dry except for a bit of runoff from the air filter. Would the oil come up through the crank case breather or back from the cylinder through the carb into the airbox?

**edit - The runoff I mention is from the foam filter oil I used, I believe. I didn't sniff, touch, or taste to confirm.

Also, will it hurt anything if I ride the bike in its current state? The DR is my only vehicle which I use to get to and from work and school everyday. Since the rain let up, I'd like to go for a quick ride to confirm the trouble I was having earlier.

could someone please tell me why you would need to be at TDC to replace the cam chain tensioner gasket?

My guess is your timing is fine unless you did something else you haven't mentioned.

The bike could be running funny because of the oil getting somewhere it shouldn't be. - what does the plug look like? assuming the oil level is normal now then riding it is probably OK but I would look at that plug and make sure it isn't lean. This is an interesting one - feels like a piece of the puzzle is missing. have you cleaned all the oil off the outside of the bike including under the tank etc..?

I just reread your last post about it being raining. Misfires are often electrical. hmmmm.

With the piston at TDC the valves will all be closed and there will be no chance of tension on the cam chain. If the piston is not at TDC of the compression stroke there is a chance, a chance, that one of the rocker arms will be positioned just so on the cam that the valve spring tension will "squirt" the cam to a different position when you remove the cam chain tensioner, allowing the cam chain to jump on the sprocket.

Personally? I wouldn't ride the bike until I was able to confirm the cam chain hasn't jumped a notch. Your description of the backfiring is pretty classic for a miss-timed engine.

Was the bike running fine before you replaced the gasket?

Did you do anything else to the bike at the same time that could be affecting how it's running?

The other question, I just thought of, is; Did you make sure to retract the tensioner plunger before you bolted the tensioner back in place? Story is that, if you leave the tensioner extended when you put it back in, you stand a chance of stretching, or breaking, the cam chain.

Please remember, the information I'm passing on to you was stuff I've read on various internet sources and we all know that there are never, ever, any doom and gloom discissions on the internet.

Now, if you'll excuse me while I go and listen to my 3rd gear whine for a moment.

The bike was running fine before I replaced the gasket, though there was a disconcerting noise when I hammered on the throttle. It sounded like something was loose, but loose and big so it made a rapid, low thunking sound. I rode it to and from work this morning and everything seems fine, even a bit better than before.


The steps I took to replace the cam chain tensioner were:

Remove the clutch arm at the crankcase
Pull one plug
Set engine to TDC using crank hole and inspection hole
Drain the oil (you'll see why in a second)
Remove the oil pipe that runs from crank case to cylinder
Remove the cam chain tensioner
Make new gasket
Reinstall cam chain tensioner while keeping plunger retracted, using a tiny screwdriver and my magic third hand
Reinstall oil pipe
Reinstall clutch arm
Close up crank hole and inspection hole
Replace oil
Reinstall plug
Start bike up

I must have not connected the spark plug boot to the spark plug well when I put the plug back in, because I removed it and put it back on last night and I've not had any problems with it today. Also, it was raining very hard last night, but the bike's never given me problems in the rain, so it must have been the combination of the two.

I didn't want to remove the header pipe because I didn't have the gaskets to replace the ones I'd surely mess up in the process. The bike doesn't seem to be dripping oil anywhere, so if things continue as they are, I'll call it good in a day or two.

Thanks a bunch for everyone's help!